Thanks to this application of nuclear medicine, it is now possible to transport radioactive materials to the precise area of a tumor to treat it, without affecting healthy cells and tissues.
What is theranostics?
The use of molecules to safely transport radioactive materials inside the human body helps doctors to obtain more precise images of the tumors and thus eliminate cancerous cells more effectively. This method combines the therapeutic use of radiopharmaceuticals and is known as Theranostics.
“Theranostics has the potential to change the idea of cancer treatment,” said Mohamad Haidar, Associate Professor at the American University of Beirut Medical Center in Lebanon. “It is a very efficient approach that allows you to see what you treat and treat what you see. The result is a better quality of life, improved life expectancy and minimal side effects compared to other treatments like chemotherapy.”
The result of theranostics therapy is a better quality of life, improved life expectancy and minimal side effects
New advances, new treatments
Theranostics has been in use for over 70 years for some specific diseases such as thyroid cancer, but it only started to take off in recent decades. Medical and technological advances have led to the development of new radiopharmaceuticals and medical equipment, and this opens the door to theranostics in the treatment of prostrate, liver, gastrointestinal and nervous system cancers, among others. This includes treating neuroendocrine tumors with a radiopharmaceutical known as lutetium-177 (Lu-177)-DOTATATE.
Although theranostics offer the possibility to improve the patients’ prognosis, it is not yet available on a large scale. This method requires special facilities, different from those used for other oncological treatment methods such as radiotherapy, chemotherapy and surgery.
“Through IAEA support, countries around the world are setting up facilities and receiving training in nuclear medicine and radiotherapy, and, when ready, safely transitioning to personalized medicine and advanced methods such as theranostics and stereotactic body radiation therapy (SBRT)”, Said May AdbelWahab, director of the IAEA’s Division of Human Health.
How does theranostics work?
Theranostics works just like any other medical drug: it interacts with the protein molecules or receptors in the cell walls. As the receptors are activated, they send an electric or biochemical signal that tells the cell what it must do, such as stop producing the chemical substances that send pain signals to the brain.
The same thing happens with radiopharmaceuticals: the radioactive materials are linked to molecules that are selected based on how they interact with the body in the presence of certain cancers. These molecules carry the radioactive materials to the target tumor, where the diagnostic imaging or treatment is applied. As healthy cells do not have the same receptors as the target cells, the radiopharmaceuticals bypass them and do not damage them.
According to Diana Paez, head of the IAEA’s Nuclear Medicine and Diagnostic Imaging Section, “with an approach that focuses on the specific needs of each patient, theranostics provides a transition from conventional medicine to personalized and precision medicine; the result is the selection of the right therapy for the right patient.”
Theranostics provides a transition from conventional medicine to personalized and precision medicine
First you see it and then you treat it
For dianostic imaging, radiopharmaceuticals with small amounts of radioactive materials are injected, ingested or inhaled and thus travel down the body to the target area. When the pharmaceutical accumulates inside or around the target cells, the small amount of radiation emitted by the radiopharmaceutical is scanned and detected with a special camera. This then produces images from that area in the body.
With the results from the diagnostic image, the doctor determines the type of treatment that works best for the patient. If the theranostics is appropriate, a radiopharmaceutical is selected for this patient, followed by the exact amount of radiation necessary for the treatment. The dose depends on the type and amount of the tumor, the patient’s age and gender, the severity of the case and the target organ. When the radiopharmaceutical accumulates inside or around the cancerous cells, its radiation damages and kills them whilst minimizing damage to the surrounding healthy cells. Patients usually have several treatment sessions, and more diagnostic imaging is done to monitor the process.
“We have seen responses to theranostic treatment that were nearly impossible with other kinds of treatment,” Haidar said.
“For example, I had an 82-year old patient with prostate cancer that had spread to the lymph nodes and bones, and after failed treatment using other methods, we switched to theranostics,” he said. “After two doses with lutetium-177 prostratespecific membrane antigen (PSMA), we saw a significant drop in tumor lessions, and then, after an additional dose with another radiopharmaceutical, actinium-255 PSMA, near complete remission.”
These are just preliminary findings, says Haidar; there is still a lot of work to do in the field of theranostics in order to gain better understanding of its impact and reach. Via its technical copperation program, IAEA provides information and donates equipment to Lebanon to support the development of its oncological treatment services.
“In the future, we could see an expansion of theranostics into use for breast and lung cancers,” he said. “If we can find a molecule that works specifically for these very common cancers, it could have a big impact on cancer survival rates and quality of life.”